I wish to detect when the user taps on the keyboard's change input language button. I'm using notification centre to do the detection.

My problem exists in the method that gets called by the notification observer. The called method does not execute beyond the first print statement. Is there something wrong with the binding of the notification object to the 'inputMode' let constant?

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    NotificationCenter.default.addObserver(self, selector: #selector(inputModeDidChange(_:)), name: UITextInputMode.currentInputModeDidChangeNotification, object: nil)
    loadLanguages()
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
NotificationCenter.default.removeObserver(UITextInputMode.currentInputModeDidChangeNotification)
}

@objc func inputModeDidChange(_ notification: Notification) {
    print("inputModeDidChange notification in languagesView fired!")
    if let inputMode = notification.object as? UITextInputMode {                           
        print("inside inputMode in inputModeDidChange in languagesView")
        if let language = inputMode.primaryLanguage {
            print("inside language in inputModeDidChange in languagesView")
            keyboardLanguage = language
            UserDefaults.standard.set(keyboardLanguage, forKey: "keyboard")
            print("keyboardLanguage in inputModeDidChange in languagesView is: \(keyboardLanguage ?? "")")
        }
    }
}